Embodiments of the inventive concepts relate generally to a method of manufacturing an alignment substrate and a liquid crystal display panel having the same.
A liquid crystal display panel typically includes a first substrate having a plurality of pixel electrodes, a second substrate facing the first substrate and having a common electrode, and a liquid crystal layer interposed between the first and second substrate. When a voltage is applied between the pixel electrode and the common electrode, an arrangement of liquid crystal molecules in the liquid crystal layer may be changed to adjust optical transmittance through the display panel, and an image can be displayed.
Liquid crystal display panels have, generally, one of two operating modes: a twisted nematic (TN) mode and a vertical alignment (VA) mode. In a TN mode device, the liquid crystal molecules interposed between the first and second substrates have an initial orientation in which the molecules are twisted by 90 degrees. When an electric field is applied, the molecules untwist in proportion to the electric field and the orientation of the liquid crystal molecules is re-arranged in a direction of the applied electric field. In a VA mode device, liquid crystal molecules with negative dielectric anisotropy may be used. In this case, the liquid crystal molecules have an initial orientation vertical (i.e. perpendicular) to a top surface of the first substrate, and when an electric field is applied, the orientation of the liquid crystal molecules may be re-arranged, or tilted, by an applied electric field.
Since VA mode devices were initially developed, there have been many techniques devised for realizing a wide viewing angle. For example, MVA or PVA mode devices having a protrusion or slit provided on the second substrate. In the MVA and PVA mode devices, directors of the liquid crystal molecules may be oriented toward several different directions, and this enables improved wider viewing angle.
In addition, to diversify orientations of the liquid crystal molecules, a method of manufacturing an alignment substrate has been developed in which a surface structure is provided. The surface structure may be formed by forming particles, on the substrate having sizes on the order of micrometers or nanometers. The alignment substrate may be a substrate including an alignment layer. Due to the presence of the surface structure, the orientation of liquid crystal can be diversified, such that the liquid crystal display panel can have an improved viewing angle property.
Generally, the particles are provided on a substrate using a spraying method. In this case, the particles may be weakly attached on the substrate, such that they may be removed from or relocated on the substrate by an external impact or a flow of fluid occurring on the substrate. As a result, the number of particles provided on the substrate may be reduced, and this may lead to a deterioration in the viewing angle. Furthermore, to diversify the size of the particles, colloidal particles having a desired size should be independently prepared. This may result in an increase of manufacturing cost.
Particles having a particle size on the order of micrometers or nanometers are typically used for such alignment substrates. If metallic particles are used, a deterioration of brightness can occur because the metallic particles are opaque.